Which formula represents a polar molecule? (1) H2 (3) CO2 (2) H2O (4) CCl4

If you added 45,000 calories to water that was at 25 degrees C, and the ending temperature was 35 degrees C, how much water did

user100 [1]

Answer:

4.5 L water we have in litres (L).

Explanation:

$Q=m\times c \times \Delta T$

where

$\Delta T$ = Final T - Initial T

Q is the heat energy in calories

c is the specific heat capacity (for water 1.0 cal/(g℃))

m is the mass of water

Plugging in the values

$\\$45000 \mathrm{cal}=m \times 1.0 \frac{\mathrm{cal}}{\mathrm{g}^{\circ} \mathrm{C}} \times\left(35^{\circ} \mathrm{C}-25^{\circ} \mathrm{C}\right)$\\\\$45000 \mathrm{cal}=m \times 1.0 \frac{\mathrm{cal}}{\mathrm{g}^{\circ} \mathrm{C}} \times 10^{\circ} \mathrm{C}$\\\\$m=\frac{45000 \mathrm{cal}}{1.0 \frac{\mathrm{cal}}{\mathrm{g}^{\circ} \mathrm{C}} \times 10^{\circ} \mathrm{C}}$\\\\$m=4500 \mathrm{g}$\\\\Density of water $=\frac{\text { mass }}{\text { volume }}$$

So,

Volume of water = mass/density

$\\\\=\frac{4500 \mathrm{g}}{\frac{1.09}{\mathrm{mL}}}=4500 \mathrm{mL}$$$

=4.5 L (Answer)

6 0

3 years ago

The small bags of silica gel you often see in a new shoe box are placed there to control humidity. Despite its name, silica gel

Zinaida [17]

So we look equation for the free Gibbs free energy (ΔG) which depends on entalpy (ΔH), temperature (T) and entropy (ΔS):

ΔG = ΔH - TΔS

ΔG is negative (-) because the water absorption on the silica gel surface is a spontaneous process.

ΔH is negative (-) because the water absorption on the silica gel surface is a exothermic process (it releases heat and if you want to desorb the water form the silica gen you need to add heat which is a endothermic process).

ΔS is negative (-) because the water is adsorbed, so from disorderly state you take the water molecules and put them in a orderly state and by doing that you decrease the entropy.

6 0

3 years ago

The addition of 250.0 J to 30.0 g of copper initially at 22.0°C will change its temperature to what final value? (Specific heat

WINSTONCH [101]

Answer:

Final temperature = $43.53^{\circ} C$

Explanation:

Given that,

Heat added, Q = 250 J

Mass, m = 30 g

Initial temperature, T₁ = 22°C

The Specific heat of Cu= 0.387 J/g °C

We know that, heat added due to the change in temperature is given by :

$Q=mc\Delta T\\\\Q=mc(T_2-T_1)\\\\\dfrac{Q}{mc}=(T_2-T_1)\\\\T_2=\dfrac{Q}{mc}+T_1$

Put all the values,

$T_2=\dfrac{250}{30\times 0.387}+22\\\\=43.53^{\circ} C$

So, the final temperature is equal to $43.53^{\circ} C$ .

8 0

3 years ago

Write in which of these processes heat is absorbed or releases heat.

neonofarm [45]

Answer:

1. Endothermic process

4Exothemic process

3 0

2 years ago

Cycloheptatrienone is stable, but cyclopentadienone is so reactive that it can't be isolated. Taking into account the polarity o

Lorico [155]

Answer and Explanation:

The resonance contributor in cyclopentadienone (as shown in the attachment below) results into the compound having a positive charge on the carbonyl group, C=O which accounts for a highly reactive anti-aromatic 4π system. And this illustrates the reason for its instability.

3 0

3 years ago